sdvl.c File Reference

Self-Describing Variable-Length (SDVL) encoding. More...

#include "sdvl.h"
#include "rohc_bit_ops.h"
#include <assert.h>

Include dependency graph for sdvl.c:

Enumerations
enum	rohc_sdvl_max_value_t { ROHC_SDVL_MAX_VALUE_IN_1_BYTE = ((1 << ROHC_SDVL_MAX_BITS_IN_1_BYTE) - 1), ROHC_SDVL_MAX_VALUE_IN_2_BYTES = ((1 << ROHC_SDVL_MAX_BITS_IN_2_BYTES) - 1), ROHC_SDVL_MAX_VALUE_IN_3_BYTES = ((1 << ROHC_SDVL_MAX_BITS_IN_3_BYTES) - 1), ROHC_SDVL_MAX_VALUE_IN_4_BYTES = ((1 << ROHC_SDVL_MAX_BITS_IN_4_BYTES) - 1) }

Functions
bool	sdvl_can_value_be_encoded (const uint32_t value)
	Can the given value be encoded with SDVL? More...
bool	sdvl_can_length_be_encoded (const size_t bits_nr)
	Is the given length (in bits) compatible with SDVL? More...
size_t	sdvl_get_min_len (const size_t nr_min_required, const size_t nr_encoded)
	Find out how many SDVL bits are needed to represent a value. More...
size_t	sdvl_get_encoded_len (const uint32_t value)
	Find out how many bytes are needed to represent the value using Self-Describing Variable-Length (SDVL) encoding. More...
bool	sdvl_encode (uint8_t *const sdvl_bytes, const size_t sdvl_bytes_max_nr, size_t *const sdvl_bytes_nr, const uint32_t value, const size_t bits_nr)
	Encode a value using Self-Describing Variable-Length (SDVL) encoding. More...
bool	sdvl_encode_full (uint8_t *const sdvl_bytes, const size_t sdvl_bytes_max_nr, size_t *const sdvl_bytes_nr, const uint32_t value)
	Encode a value using Self-Describing Variable-Length (SDVL) encoding. More...
size_t	sdvl_decode (const uint8_t *const data, const size_t length, uint32_t *const value, size_t *const bits_nr)
	Decode a Self-Describing Variable-Length (SDVL) value. More...

Detailed Description

Self-Describing Variable-Length (SDVL) encoding.

Author

Didier Barvaux didie.nosp@m.r.ba.nosp@m.rvaux.nosp@m.@tou.nosp@m.louse.nosp@m..viv.nosp@m.eris..nosp@m.com

Didier Barvaux didie.nosp@m.r@ba.nosp@m.rvaux.nosp@m..org

Enumeration Type Documentation

rohc_sdvl_max_value_t

enum rohc_sdvl_max_value_t

The maximum values that can be SDVL-encoded in 1, 2, 3 and 4 bytes

Enumerator
ROHC_SDVL_MAX_VALUE_IN_1_BYTE	Maximum value in 1 SDVL-encoded byte
ROHC_SDVL_MAX_VALUE_IN_2_BYTES	Maximum value in 2 SDVL-encoded byte
ROHC_SDVL_MAX_VALUE_IN_3_BYTES	Maximum value in 3 SDVL-encoded byte
ROHC_SDVL_MAX_VALUE_IN_4_BYTES	Maximum value in 4 SDVL-encoded byte

Function Documentation

sdvl_can_length_be_encoded()

bool sdvl_can_length_be_encoded

(

const size_t

bits_nr

)

Is the given length (in bits) compatible with SDVL?

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Parameters

bits_nr

The length (in bits) of the value to encode

Returns

Whether the value can be encoded with SDVL or not

sdvl_can_value_be_encoded()

bool sdvl_can_value_be_encoded

(

const uint32_t

value

)

Can the given value be encoded with SDVL?

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Parameters

value

The value to encode

Returns

Whether the value can be encoded with SDVL or not

sdvl_decode()

size_t sdvl_decode	(	const uint8_t *const	data,
		const size_t	length,
		uint32_t *const	value,
		size_t *const	bits_nr
	)

Decode a Self-Describing Variable-Length (SDVL) value.

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Parameters

data	The SDVL data to decode
length	The maximum data length available (in bytes)
value	OUT: The decoded value
bits_nr	OUT: The number of useful bits

Returns

The number of bytes used by the SDVL field (value between 1 and 4), 0 in case of problem

sdvl_encode()

bool sdvl_encode	(	uint8_t *const	sdvl_bytes,
		const size_t	sdvl_bytes_max_nr,
		size_t *const	sdvl_bytes_nr,
		const uint32_t	value,
		const size_t	bits_nr
	)

Encode a value using Self-Describing Variable-Length (SDVL) encoding.

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Encoding failures may be due to a value greater than 2^29.

Parameters

sdvl_bytes	IN/OUT: The SDVL-encoded bytes
sdvl_bytes_max_nr	The maximum available free bytes for SDVL
sdvl_bytes_nr	OUT: The number of SDVL bytes written
value	The value to encode
bits_nr	The number of bits to encode

Returns

true if SDVL encoding is successful, false in case of failure

sdvl_encode_full()

bool sdvl_encode_full	(	uint8_t *const	sdvl_bytes,
		const size_t	sdvl_bytes_max_nr,
		size_t *const	sdvl_bytes_nr,
		const uint32_t	value
	)

Encode a value using Self-Describing Variable-Length (SDVL) encoding.

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Encoding failures may be due to a value greater than 2^29.

Parameters

sdvl_bytes	IN/OUT: The SDVL-encoded bytes
sdvl_bytes_max_nr	The maximum available free bytes for SDVL
sdvl_bytes_nr	OUT: The number of SDVL bytes written
value	The value to encode

Returns

true if SDVL encoding is successful, false in case of failure

sdvl_get_encoded_len()

size_t sdvl_get_encoded_len

(

const uint32_t

value

)

Find out how many bytes are needed to represent the value using Self-Describing Variable-Length (SDVL) encoding.

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Parameters

value

The value to encode

Returns

The size needed to represent the SDVL-encoded value

sdvl_get_min_len()

size_t sdvl_get_min_len	(	const size_t	nr_min_required,
		const size_t	nr_encoded
	)

Find out how many SDVL bits are needed to represent a value.

The number of bits already encoded in another field may be specified.

See 4.5.6 in the RFC 3095 for details about SDVL encoding.

Parameters

nr_min_required	The minimum required number of bits to encode
nr_encoded	The number of bits already encoded in another field

Returns

The number of bits needed to encode the value